XBOX gamebar volume control doesnt work

Hi;
Apologies for this obviously unintended bug on behalf of the team, and thanks for the report, I’ll make sure it gets noticed.
This is my standard list of simple settings to check first:

I usually add this tip by @vincent to that list:

Two suggestions you could perhaps give a careful try, by @Brock and @Dolmatov, concerning the “Default Device” settings (and yes, I am quite aware they contradict my own advice given above):

Please give these suggestions a try, and post back with your results.
If the issue persists, we can explore further steps.